All Small Six Valve Seals and Compression

[gserafini]

As usual more fun things come up as you dive deeper! Seems like I may have some leaking seals. These plugs don’t have too many miles on them overall maybe a year old. Couple questions after seeing this and testing.
1. Anyone use the Viton 0.530 seals from Vintage Inlines and do they fit a stock on the 66 200?
2. Anything else I should look at closer while I have this valve cover off? Or anything you notice/ stand out from the photos?

Appreciate the experienced input from this group, as calling myself a weekend mechanic is even too generous ha!

 

[B RON CO]

Hi, of course you know that the valve stem seals have nothing to do with the compression. I am not sure, but I believe the top of the guides have to be machined to accept anything other than the stock umbrella seal. I would check the lash on # 3, if the adjustment is too tight, the valves may not be fully closed. If you measure poor or bouncing vacuum, loosen the adjustment. The plugs look a little rich, make sure the choke is fully open and held open with spring pressure when the engine is warm. Good luck

 

[gserafini]

Oh yes, I just saw the oil buildup on the plugs when doing the compression test, which pointed me to look at the seals. Figured I’d just include the photos in case it pointed to anything else. Thank I will check that! And I’ll look up the size on the stock bushings also to compare

 

[Frank]

Oh yes, I just saw the oil buildup on the plugs when doing the compression test, which pointed me to look at the seals. Figured I’d just include the photos in case it pointed to anything else. Thank I will check that! And I’ll look up the size on the stock bushings also to compare

If machining the head is not in the loop right now, a new set of umbrella seals goes a long way toward minimizing oil intrusion via the guides. Disclaimer, I do not have direct experience with the small6.
Assure the oil drain-back holes are all fully functional. Oil accumulating above the head can- does- greatly increase oil consumption if it gets deep enough and guides are old. Verifying the PCV system is functioning correctly plays a role here as well.
As you're aware, the majority of oil intrusion into the air/fuel charge occurs on the intake valves, as the guide is exposed to manifold vacuum when the valve is open, any excess oil on the stem is drawn into the airstream.

Some indicators of leaky valve guides: a puff of blue oil smoke after an idle period, long idle= more smoke. Becomes worse the hotter the engine is. 2) Staring the engine hot, a puff of oil smoke. On hard acceleration or high speed cruise the smoke clears to none.

Peace.

 

[gserafini]

Awesome, thanks! So many things keep pointing me towards pulling it and doing a mild rebuild/refresh. Not sure that's in the cards right now time or money wise. one step at a time!

 

[Frank]

one step at a time!

Other than embarrassment at the smoke, adding oil occasionally, and gradually fouling plugs, oily valve guides are not hurting anything. I am very familiar with oily guides: I ran Chevys for decades, including the era when lead was removed from gas. Old engines that transitioned to unleaded frequently developed valve issues, as lead served as a lubricant for the seats and to some degree, the stems.

 

[gserafini]

Ahh this makes sense! Definitely not embarrassed about blowing some smoke...she's a driving fixer right now ha!

 

[DON]

I believe as well that the head needs to be machined for the positive seals. I’m not sure what is involved in the machining process

 

[Frank]

I believe as well that the head needs to be machined for the positive seals. I’m not sure what is involved in the machining process

good machine shop, machining process simple- removing the head is the hard part!

 

[DON]

I was thinking more along the line of the tool to do it. It’s pretty much a given that the head isn’t going to spin in the process, so it must be some kind of bit for a milling machine type of tool.